THERMAL CONDUCTIVITY IMPROVEMENT OF LUNAR REGOLITH SIMULANT
Lunar regolith can be appropriated to solar thermal energy storage and electrical power generation by use of the improvement of thermal conductivity. Lunar regolith simulant (LRS-1), the research object of this paper, was given the microstructure and element composition by use of scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). A variety of processing methods were used to modify the thermal conductivity of LRS-1, such as particle sieving, compacting, heating up to sintering and melting under air atmosphere. Four samples were fabricated, including two particle diameter sizes, ∅500µ m and ∅100µ m, and two heating temperatures, 1100°C and 1200°C. The XRD results showed that the sintering and melting processes transformed the crystalline structure of lunar regolith simulant into amorphous structure. The thermal conductivity tester results showed that compacting, sintering and melting processes had improved the thermal conductivity of lunar regolith simulant indeed. The thermal conductivities of sintered and melted samples had been raised hundreds of times as against the native lunar regolith. The particle size also a key factor to influence the thermal conductivity besides the heating temperature. The SEM images of different particle size samples indicated that the porosity increased with particle size under same heating temperature. The particle size was much larger, the thermal conductivity were much lower. Furthermore, it found that the melted sample for ∅100µ m particle size reached the maximum thermal conductivity value.